Hydraulic pressure driven rotary toothbrush

ABSTRACT

A rotary toothbrush comprises a hand held housing and a toothbrush interchangeably mounted on a rotary shaft journalled in the housing. The housing has a chamber wherein a turbine wheel is mounted for rotating the shaft when water under pressure is supplied to the housing chamber. A manually operable control is mounted on the housing to drive the wheel in either direction or to stop it, and a water ejector means in the housing chamber causes a pressure reduction in the chamber between the turbine wheel and a water outlet for facilitating drainage of water. Channels in the shaft supply rinsing water from the housing chamber to the brush.

1 States 1191 1111 3,909,867

Hogsell Oct. 7, 1975 HYDRAULIC PRESSURE DRIVEN ROTARY TOOTHBRUSH PrimaryExaminer-Edward L. Roberts [76] Inventor: Gunnar Hogsell, Boplatsvagen6, Attorney Agent or firm-min Kelman S-291 65 Kristianstad, Sweden [22]Filed: Sept. 13, 1974 [57] ABSTRACT [21] Appl. No.: 505,986

A rotary toothbrush comprises a hand held housing [30] ForeignApplication Priority Dat and a toothbrush interchangeably mounted on arotary Sept. 20, 1973 Sweden 7312796 Shaft journaued in the housing Thehousing has a chamber wherein a turbine wheel is mounted for ro- 52 us.(:1. 15/24; 32/26; 415/503 e the Shaft when Water under Pressure isSupplied 51 11m. 01. A61C 17/02; A46B 13/06 the housing ehemher- Amanually Operable Control [58] Field of Search l5/22 R, 23, 24 28 29, ismounted on the housing to drive the wheel in either /97 32/26, 27, 28,59; 415/503 direction or to stop it, and a water ejector means in thehousing chamber causes a pressure reduction in [56] References Cited thechamber between the turbine wheel and a water UNITED STATES PATENTSoutlet for facilitating drainage of water. Channels in the shaft supplyrinsing water from the housing cham- 3,046,585 7/1962 Ledingham et al.15/24 her to the brush 3,553,758 l/l97l Wood 15/24 FOREIGN PATENTS ORAPPLICATIONS 15 Claims 10 Drawing Figures 503,568 12/1954 Italy 415/503Oct. 7,1975 Sheet 1 of 4 3,909,867

US. Patent US. Patent Oct. 7,1975 Sheet 2 of4 3,909,867

US. Patent Oct. 7,1975 Sheet 3 of4 3,909,867

US, Patent 0012. 7,1975 Sheet4 of4 3,909,867

HYDRAULIC PRESSURE DRIVEN ROTARY TOOTHBRUSH The present inventionrelates to improvements in a hydraulic pressure driven rotarytoothbrush.

Conventional toothbrushes, while simple and convenient, do not meet therequirements of modern dental hygiene. Efficient dental cleansingrequires brushing to be performed in such a manner as to preventbacteria and food particles from being pressed into pockets between thegum and the base of the teeth. This makes it necessary to twist thewrist While brushing with an ordinary toothbrush. The corresponding handmovements are complex and are difficult to perform, particularly bychildren or people deprived of easy movement of the hand and/or arm.

In an effort to obtain more effective dental cleansing,

,various electrically powered toothbrushes have been designed for rotaryas well as oscillatory brushing movements. Since the electric motor forsuch brushes must obviously be small to be accommodated in the brushhandle, it has a correspondingly low output efficiency.

Furthermore, it is desirable to rinse the toothbrush during brushing tomake the cleaning effective while, at the same time, holding Waterconsumption to a minimum for the entire operation which should take atleast about 2 minutes for a thorough brushing to the teeth.

It is the primary object of this invention to provide an efficientrotary toothbrush meeting the requirements of modern dental hygienewhile requiring a minimum supply of water for operating the brush andrinsing the teeth during brushing continuously.

The above and other objects are accomplished in accordance with theinvention with a rotary toothbrush which comprises a hand held housingand an interchangeable brush. A miniature motor, such as a turbineoperable by hydraulic pressure, is mounted in the housing and a rotaryshaft is operably associated with the motor for rotation about the axisthereof, preferably by means of a planetary or like reduction gearing toreduce the relatively high velocity of the turbine to a lower rotaryvelocity of the shaft on which the brush is detachably mounted. Thehousing defines chamber means to which water is supplied under pressurethrough an inlet, flows through the housing chamber to operate the motorand rotor the shaft, and is drained through a water outlet. A watercontrol including a valve is arranged on the housing for readymanipulation to control the water flow for blocking it from the mo tor,rotating the shaft in a first direction and reversing the rotationaldirection of the shaft. Channel means in the rotary shaft and the brushis in communication with the housing chamber for receiving rinsing watertherefrom and conveying it to the brush whereby the same water supply isused for operating the motor and delivering rinsing water to the brush.The used water is sucked away by means causing a pressure reduction inthe housing chamber between the motor and the water outlet to assistdrainage of waste water from the motor.

The above and other objects, advantages and features of the presentinvention will become more apparent from the following detaileddescription of now preferred embodiments thereof, taken in conjunctionwith the accompanying drawing wherein FIG. l is a perspective view of ahand-held rotary toothbrush connected to the faucet of a wash basin;

FIG. 2 is an axial section of the toothbrush;

FIG. 3 is a transverse section along line lII-III of FIG. 2, showing acontrol device for reversing the rotary direction of the brush;

FIG. 4 is a transverse section, on an enlarged scale, along line lV-IVof FIG. 2, showing a planetary gearing for reducing the revolutions ofthe rotary brush;

FIG. 5 is an axial section, on an enlarged scale, showing a detail ofthe structure;

FIGS. 6 to 8 are enlarged sections illustrating different positions ofthe turbine wheel;

FIG. 9 is a perspective view of an alternative embodiment of the brush;and

FIG. 10 is a transverse section along line XX of FIG. 9, showing anarrangement for the detachable connection of the brush and protectiveshield.

Referring now to the drawing and first to FIG. 1, there is shown arotary toothbrush 1 powered by water pressure, a flexible tube 2 havingone end connected to faucet 3 on wash basin 4 by means of connector 5while the other tube end is connected to the toothbrush. As shown in thedrawing, the toothbrush has a section shaped to be gripped firmly byhand 6 of a user so that the user may comfortably perform all brushmovements. For the sake of clarity, toothbrush 1 has been shown on alarger scale than the wash basin and other attachments.

The longitudinal section of FIG. 2 illustrates the toothbrush structure.As shown, the toothbrush comprises hand gripping section 7 and brushmeans 8 partially surrounded by protective shield 9. The hand grippingsection of the toothbrush consists essentially of housing part 12 andcover part 3 which together define and enclose a chamber housing therotary drive mechanism and necessary water passages. The power drive isprovided by turbine wheel 14 keyed to turbine shaft 16. The turbineshaft is journalled in bearing plate 17 and has an end 19 projectinginto axial bore 28 at the inner end of rotary shaft 18 carrying thebrush. The bearing plate is carefully machined to fit into the chamberdefined by housing 12 and has skirts l9 and 21 to enable the bearingplate to be retained in the housing chamber by placing cover 13 over theopen housing end and securing it thereto by tightening screws 20. Aswill be seen in FIG. 2, the rim of cover 13 presses against skirt 19 ofthe bearing plate and opposite bearing plate skirt 21 simultaneouslypresses against a flange of bushing 22, thus holding the bushing flangeagainst a shoulder in the housing chamber and retaining the bushingfirmly therein.

Hand gripping section 7 has a cylindrical portion projecting therefromand housing planetary gearing 15 shown best in FIG. 4. The planetarygearing comprises three planetary wheels 23, 24, 25 equidistantly spacedabout turbine shaft 16 and meshing with gearing portion 30 on the shaftas well as with gearing portion 31 on the inner surface of thecylindrical portion of the hand gripping section.

Rotary shaft 18 has an enlarged end section 27 forming a squirrel s cagewith three openings 32 housing the planetary wheels, shaft end section27 being housed in the cylindrical portion of hand gripping section 7and carrying axles 26 whereon the planetary wheels are mounted.

Cylindrical portion 33 of rotary shaft 18 projects from its end section27 and is journalled in axial bore 34 of the cylindrical portion of handgripping section 7.

O-ring or an equivalent sealing means is arranged in an annular groovein bore 34. The end of cylindrical shaft portion 33 projecting beyondhousing 12 carries a preferably coarse thread 36, followed by conicalpart 37. The thread on the cylindrical shaft portion may be replaced bya bayonet or similar joint for attaching the brush to the shaft. Axialbore 38 passes from bore 28 through shaft 18 for conveying rinsing waterto brush means 8.

The brush means comprises a brush part 39 mounted on support 40 formedwith conical axial recess 42 confirming to conical part 37 and thread 41to mesh with thread 36 for attachment of the brush means to rotary shaft18. Support 40 has axial bore 43 aligned with bore 38 and incommunication with discharge ports 44 for passing rinsing water to thebrush part. As shown, support 40 is knurled at 47 to enable it to begripped firmly for threadedly connecting the support to the shaft. Whenthe brush means is mounted on the rotary shaft, support 40 must bescrewed so tightly on shaft 18 that the conical surfaces 37 and 42 forma tight seal. Therefore, shaft 18 must be held against rotation whenbrush means 8 is emplaced or removed. For this purpose, the followinglocking arrangement is provided for rotary shaft 18:

The outer, ring-shaped part of rotary shaft end section 27 carriessector-shaped projections 45 facing corresponding projections 46 on theend face of bushing 22. When shaft 16 is in its freely rotatableposition, as shown in FIG. 2, there is an axial gap S betweenprojections 45 and 46. The shaft is mounted in housing 12 for axialdisplacement by a distance S exceeding the length of gap S Simple manualpressure on support 40 will slide shaft 18 down in the direction of handgripping section 7 until projections 45 and 46 engage and thus preventthe shaft from turning about its axis. Thus held against rotation, theshaft can now be joined tightly with support 40 of brush means 8 or thesupport may be removed therefrom. In use, shaft 18 will be axially movedupwardly again into the position shown in FIG. 2.

The turbine wheel structure and operation is best shown in FIGS. 6 to 8.Turbine wheel 14 has vanes 48 shaped to be operated by jets of water forrotation clockwise or counterclockwise. Valve 49 cooperates with theturbine wheel, three different operating positions being shown in FIGS.6 to 8.

Adjustable valve 49 is mounted for turning in bushing 22 fixedly held inhousing 12 in a manner previously described. As best shown in FIG. 3,the valve may be adjusted into different positions by control rod 50which is mounted for sliding movement in housing 12, the axis ofslidable rod 50 extending transversely to the axis of rotary shaft 16and rod 50 being reciprocable in the direction of double-headed arrow PThe valve has a cylindrical portion 52 journalled in bushing 52 and thecylindrical valve portion has a gear segment 53 meshing with rack 51forming the central portion of control rod 50. When the control rod ismanually moved, by simple thumb pressure on rod ends 54, 55, forinstance, in the direction of arrow P the valve will be turned inrelation to bearing plate 17 fixedly retained in housing 12. Two O-rings55, 56 near respective rods ends 54, are mounted in circumferentialgrooves in rod 50. These O-rings serve the double function of providinga seal between the rod and housing 12 and also tend because of theirinherent resilency to retain the rod in each adjusted axial position, aswill be described in detail hereinafter. The three positions of thecontrol rod are determined by the positions of three annular grooves 57,58, 59 in housing 12in the path of the axial movement of control rod 50.As the rod is axially moved, the O-rings will enter a respective one ofthe annular grooves, as illustrated by groove 58 in FIG. 3, thus beingresiliently retained in the respective position without being lockedthereinto against further axial movement by a relatively light pressureof the thumb.

The three mentioned positions of rod 50 correspond to the threepositions of valve 49 shown in FIGS. 6 to 8. The valve has at least oneport 60 for alignment with oblique port 61 or 62 in bearing plate 17. Inthe first position shown in FIG. 6, valve port 60 is in communicationwith bearing plate port 61 to permit water under pressure to flow in thedirection of arrowP against vanes 48 of turbine wheel 14. This willbring about a clockwise rotation of the wheel and rotary shaft 16 in thedirection of arrow P In the centered position shown in FIG. 7, valveport 60 is out of communication with any bearing plate port and theturbine wheel will stand still. In the position shown in FIG. 8, valveport 60 is in communication with bearing plate port 62 to permit waterunder pressure to fiow in the direction of arrow P to turn the turbinewheel and rotary shaft 16 in the counterclockwise direction indicated byarrow P Thus, rotation of shaft 16 may be reversed or stopped by axialmovement of control rod 50.

Valve 49 is biased against bearing plate 17 be means of spring washer 63mounted between the end face of bushing 22 and the cylindrical portion52 of the valve.

In order to control the amount of rinsing water passing through axialbores 38, 43, shaft end 29 carries conical valve port 64 forming aneedle valve with the inner end of bore 38 whereinto it projects, thebore end con;

stituting a valve seat for valve part'64. As shown in FIG.

5, water under pressure is forced into annular space 65- surroundingvalve part 64 through lateral bore in shaft end section 27 in thedirection of arrow P Rotary shaft 16 is axially displaceably mounted'oncover 13, conical valve port 64 being biased into (2105- ing bore 38 bycompression spring 67 which is mounted on stop pin 71 in axial bore 69of set screw 70. The set screw is threaded into cover 13 coaxially withshaft 16 and ball 68 is interposed between end 72 of pin 71 and the endof shaft 16. The stop pin has a length selected to permit a little axialplay S between ball 68 and pin end 72 when the set screw has beenthreaded into cover 13 sufficiently to enable spring 67 to press shaft16 upwardly for moving valve part 64 into closing engagement with bore38. When water under pressure flows through valve 49 in the direction ofarrow P or P, (FIGS. 6 and 8), it will press turbine wheel 14 downwardlyagainst the bias of spring 67, the wheel being keyed to shaft 16 formovement therewith, and thus level out axial play S thus moving valvepart 64 out of engagement with bore 38 and opening the same to receive aflow of rinsing water through bore 66. Adjustment of set screw enablesthe amount, of rinsing water passing through bore 38 to be regulated.

Hydraulic pressure for turning turbine wheel 14 and shaft 16 is suppliedfrom wash basin faucet 3-by tubing I 2 which consists of flexible inlettube 1 1 surrounded by flexible outlet tube 10. One end of the tubing isdetachably mounted on connector 5 and the other tubing end is detachablymounted on nipple 73 which is integral with housing 12 and comprisesinlet 74 whereon inner tube 11 is mounted to receive water underpressure flowing in the direction of arrow P The nipple inlet widensinto chamber 75 defined by a thickened portion of the wall of housing12, which forms the nipple. Chamber 75 is in communication with annularchamber 77 through lateral port 76, valve 49 being housed in chamber 77so that water under pressure may flow through inlet 74, chamber 75, port76, chamber 77 and valve port 60 for turning turbine wheel 14. Annularchamber 77 is in communication with annular chamber 78 surrounding thecylindrical portion of valve 49 and an axial bore in the end face ofbushing 12 of a diameter larger than that of shaft 16 places chamber 78in communication with annular chamber 79 surrounding end section 27 ofshaft 18, thus permitting water to flow through lateral bore 66 in thedirection of arrow P (see FIG. 5), as previously described.

Except forturbine shaft 16, planetary wheel axles 26, spring 67 and ball68, spring 63, and possibly the O rings, brush part 39 and tubing 2, allparts of the tooth brush are preferably made of a molded syntheticresin. For this reason and due to practical production requirements,ports will be formed in the thickened portion of the wall of housing 12adjacent chamber 75, and these ports are sealed With plugs 81), 80a.

Cover 13 and bearing plate 17 define chamber 82 below and around turbinewheel 14 to receive the water flowing through valve 4-9 and operatingthe turbine wheel, chamber 82 being in communication with chamber 75through channel 81 boxed in thickened wall portion of housing 12.Channel 81 leads to the outlet of nipple 73 to which outer tube isattached.

Protective shield 9 for brush part 39 has a ringshaped connector part 83for frictional engagement with cylindrical upper section 84 of housing12 so that the shield may be detachably mounted on the toothbrush. Thismounting will be facilitated if part 83 is somewhat elastic so as to beheld firmly on housing section 84. A snap fit would also be possible.

In the modified embodiment of FIG. 9, the brush part is not an elongatedcylindrical member, as shown in FIG. 2, but consists of spiral brush 39'enhancing the cleansing effect of the brush upon rotation. Furthermore,brush protective shield 9 carries fork-shaped re tainer 85 (see FIG. 10)gripping annular groove 86 of brush support 40'. This makes it possibleto turn the shield in respect of the brush part. In either embodiment,it will be simple to remove the shield and the brush means for readyreplacement by another shield and brush means so that different personsmay use the device.

The operation of the rotary toothbrush hereinabove described will partlybe evident from the described structure and will be further detailedhereinbelow.

In use, one end of tubing 2 with connector 5 is so mounted on faucet 3that inner tube 11 is in communi cation with the faucet, which may beturned on to permit water to flow through tube 1 1 under pressure, whileouter tube 10 if open at that end to drain water from the operatingtoothbrush in the direction of arrow P (See FIG. 1). The faucet is setfor a moderate flow of water which, as shown by arrow P in FIG. 2,enters through inlet 73 and fills all the chambers in the toothbrushhousing, as indicated by the arrows in FIG. 2 which show the directionof water flow, some of the water under pressure simultaneously flowingover through channel 81 to depressurize chamber 82. If valve 49 is inits center position (see FIG. 7), turbine wheel 14lwill stand still,i.e., no rotary driving power is transmitted to the brush shaft and nowater enters chamber 82 through the valve. However, the water pressurewill axially move brush shaft 18 the distance S so that it will beunlocked if it had previously been locked for replacement of the brushmeans, as described hereinabove.

Upon manipulation of control rod 50, valve 49 will be moved into anoperating position, as indicated in FIGS. 6 or 8, so that hydraulicpressure will begin to turn the turbine wheel, the operating waterflowing out through chamber 82 and being sucked into tube 10 by thewater passing through channel 81. If desired, the direction of rotationmay be reversed during operation by manipulation of control rod 50 inthe previously described manner.

The rotary direction of the brush may be rapidly changed for every groupof teeth being brushed so that brushing is effected in a direction fromthe gum upward towards the teeth so that food particles are not presseddown between the base of the teeth and the gums. During brushing,protective shield 9 prevents brush part 39 from coming into contact withparts of the mouth which should not be touched by the brush.

The amount of rinsing Water passing through discharge ports 44 to brushpart 39 is set by screw in the manner previously described to anydesired amount. Thus, the teeth are effectively brushed andsimultaneously rinsed, the rotary control during operation beingexceedingly simple by pressure manipulation of rod 50.

Most parts of the toothbrush being of molded plastic, mass production atlow cost is available, a preferred synthetic resin for the manufactureof these molded parts being Teflon.

As shown in FIG. 2, it will be useful to place a floating anti-frictionwasher 87, for instance of Teflon or another suitable material of lowfriction coefficient, between section 27 of shaft 18 :and cylindricalportion 84 of housing 12 so as to seal off the housing chambers filledwith water during operation.

A useful material for the manufacture of turbine shaft 16, planetarywheels 23-25 and their axles 26, ball 68 and springs 67 and 63 isstainless steel.

Since all the moving parts are automatically lubricated by the flowingwater, they will be subject to slight wear only and have a longoperating life. Also, water consumption during operation is low sincethe amount of rinsing water supplied to the brush obviously must berelatively limited and the amounts of water producing the turbine wheeloperating jets through bores 61, 62 are also quite limited.

While the rotary toothbrush has been described herein in connection withcertain preferred embodiments thereof, it will be clearly understoodthat various modifications may occur to those skilled in the art,particularly after benefitting from the present teaching, withoutdeparting from the spirit and scope of this invention as defined in theappended claims.

What is claimed is:

1. A rotary toothbrush comprising a housing shaped to be hand grippedand an interchangeable brush means, a motor means operable by hydraulicpressure mounted in the housing, a rotary shaft means operablyassociated with the motor means for rotation about the axis of the shaftmeans, the shaft means projecting from the housing and the brush meansbeing detachably mounted thereon, the housing defining chamber means, aninlet for water under pressure and a water outlet, whereby watersupplied under pressure through the inlet and flowing through thehousing chamber means operates the motor means and rotates the shaftmeans, water flow control means arranged to control the water flow forblocking it from the motor means, rotating the shaft means in a firstdirection and reversing the rotational direction, channel means in therotary shaft means and the brush means in communication with the chambermeans for receiving rinsing water therefrom and conveying it to thebrush means, and means causing a pressure reduction in the housingchamber means between the motor means and the water outlet for assistingdrainage of waste water from the motor means.

2. The rotary toothbrush of claim 1, wherein the hydraulic pressureoperable motor means comprises a turbine wheel having a plurality ofvanes and arranged for rotation in reversible direction, a shaftextending through the housing, the turbine wheel being keyed to theshaft for rotating the shaft in the direction of wheel rotation, and agearing interconnecting the shaft to the shaft means whereon the brushmeans is detachably mounted.

3. The rotary toothbrush of claim 2, further comprising a bearing plateadjacent the turbine wheel, the bearing plate being fixedly mounted inthe housing and having two diagonally opposite ports obliquely inclinedin opposite directions towards the vanes of the turbine wheel, and thewater flow control means comprising a valve means having at least oneport and means for moving the valve port out of communication with thebearing plate ports and into selective communication with a respectiveone of the bearing plate ports for blocking the motor means and rotatingthe shaft means in the reversible directions.

4. The rotary toothbrush of claim 3, wherein the water flow controlmeans further comprises a control rod slidably mounted in a transversebore in the housing, the rod having opposite ends projecting from thehousing, and transmission means interconnecting the control rod to thevalve means for moving the valve port in response to sliding of thecontrol rod in the bore.

5. The rotary toothbrush of claim 4, further comprising snap meansassociated with the rod and the bore for resiliently retaining the rodin a selected one of three positions.

6. The rotary toothbrush of claim 3, further comprising spring meanspressing the valve means against the bearing plate. 7

7. The rotary toothbrush of cliam 2, wherein the gearing comprises aplanetary gear having three planetary gear wheels rotatably mounted in asection of the shaft means, a gearing portion on the turbine shaft and agearing portion on the interior wall of the housing, the planetary gearwheels meshing with the gearing portions whereby rotation of the turbineshaft is transmitted to the shaft means for rotation thereof.

8. The rotary toothbrush of claim 7, wherein the turbine shaft isaxially displaceably journalled in coaxial bores in the bearing plateand the shaft means section, the turbine shaft having an end projectingfrom the shaft means section into the channel means in the rotary shaftmeans, and the turbine shaft end carries a conical valve part wherebyaxial displacement of the turbine shaft opens and closes the channelmeans for flow of rinsing water to the brush means and shutting off therinsing water flow.

9. The rotary toothbrush of claim 8, further comprising means forcontrolling the axial displacement of the turbine shaft, thedisplacement control means including a set screw threadedly mounted inthe housing coaxially with the turbine shaft, a stop pin on the screw, acompression spring around the stop pin and a ball held between thecompression spring and the opposite end of the turbine shaft, the stoppin and ball being coaxial with the turbine shaft, axial play beingpermitted between the ball and the opposite turbine shaft end.

10. The rotary toothbrush of claim 8, further comprising a bushingfixedly mounted in the housing between the shaft means section and theturbine wheel, the bushing having an end face defining a bore throughwhich the turbine shaft extends, the bore having a diameter greater thanthe diameter of the turbine shaft, the rotary shaft means being axiallydisplaceably journaled in the housing, and axially spaced projections onthe shaft means section and the bushing end face for locking engagementupon axial movement of the shaft means in one direction whereby rotationof the shaft means is prevented and disengagement upon axial movement ofthe shaft means in the opposite direction whereby the shaft means isfree to rotate.

11. The rotary toothbrush of claim 7, further comprising a floatinganti-friction washer mounted between the shaft means section and thehousing.

12 The rotary toothbrush of claim 1, further comprising a support forthe brush means, the shaft means having a conical end and the supporthaving a conforming conical recess to receive the support on the shaftmeans end, and means for detachably holding the support on the shaftmeans end.

13. The rotary toothbrush of claim 12, further com prising a protectiveshield for the brush means, the protective shield being detachablymounted on the housing, and a fork-shaped clamping means connecting theshield to the support for free rotation of the shield in respect of, andremoval from, the support.

14. The rotary toothbrush of claim 1, further comprising a water supplyand removal tubing attached to the housing inlet and outlet, the mbingincluding an inner tube connected to the inlet for supplying water underpressure to the housing chamber means, the chamber means including afirst chamber adjacent the inlet, a second chamber wherein the motormeans is arranged, a port connecting the first and second chambers, anda third chamber wherein the rotary shaft means is arranged, the secondand third chambers being in communication, the channel means comprisinga lateral bore in the rotary shaft means in communication with the thirdchamber for receiving rinsing water from the third chamber, and thetubing including an outer tube connected to the outlet for removal ofwaste water. I

15. the rotary toothbrush of claim 14, wherein the means causing thepressure reduction comprises a channel connecting the first chamber tothe water outlet.

1. A rotary toothbrush comprising a housing shaped to be hand grippedand an interchangeable brush means, a motor means operable by hydraulicpressure mounted in the housing, a rotary shaft means operablyassociated with the motor means for rotation about the axis of the shaftmeans, the shaft means projecting from the housing and the brush meansbeing detachably mounted thereon, the housing defining chamber means, aninlet for water under pressure and a water outlet, whereby watersupplied under pressure through the inlet and flowing through thehousing chamber means operates the motor means and rotates the shaftmeans, water flow control means arranged to control the water flow forblocking it from the motor means, rotating the shaft means in a firstdirection and reversing the rotational direction, channel means in therotary shaft means and the brush means in communication with the chambermeans for receiving rinsing water therefrom and conveying it to thebrush means, and means causing a pressure reduction in the housingchamber means between the motor means and the water outlet for assistingdrainage of waste water from the motor means.
 2. The rotary toothbrushof claim 1, wherein the hydraulic pressure operable motor meanscomprises a turbine wheel having a plurality of vanes and arranged forrotation in reversible direction, a shaft extending through the housing,the turbine wheel being keyed to the shaft for rotating the shaft in thedirection of wheel rotation, and a gearing interconnecting the shaft tothe shaft means whereon the brush means is detachably mounted.
 3. Therotary toothbrush of claim 2, further comprising a bearing plateadjacent the turbine wheel, the bearing plate being fixedly mounted inthe housing and having two diagonally opposite ports obliquely inclinedin opposite directions towards the vanes of the turbine wheel, and thewater flow control means comprising a valve means having at least oneport and means for moving the valve port out of communication with thebearing plate ports and into selective communication with a respectiveone of the bearing plate ports for blocking the motor means and rotatingthe shaft means in the reversible directions.
 4. The rotAry toothbrushof claim 3, wherein the water flow control means further comprises acontrol rod slidably mounted in a transverse bore in the housing, therod having opposite ends projecting from the housing, and transmissionmeans interconnecting the control rod to the valve means for moving thevalve port in response to sliding of the control rod in the bore.
 5. Therotary toothbrush of claim 4, further comprising snap means associatedwith the rod and the bore for resiliently retaining the rod in aselected one of three positions.
 6. The rotary toothbrush of claim 3,further comprising spring means pressing the valve means against thebearing plate.
 7. The rotary toothbrush of cliam 2, wherein the gearingcomprises a planetary gear having three planetary gear wheels rotatablymounted in a section of the shaft means, a gearing portion on theturbine shaft and a gearing portion on the interior wall of the housing,the planetary gear wheels meshing with the gearing portions wherebyrotation of the turbine shaft is transmitted to the shaft means forrotation thereof.
 8. The rotary toothbrush of claim 7, wherein theturbine shaft is axially displaceably journaled in coaxial bores in thebearing plate and the shaft means section, the turbine shaft having anend projecting from the shaft means section into the channel means inthe rotary shaft means, and the turbine shaft end carries a conicalvalve part whereby axial displacement of the turbine shaft opens andcloses the channel means for flow of rinsing water to the brush meansand shutting off the rinsing water flow.
 9. The rotary toothbrush ofclaim 8, further comprising means for controlling the axial displacementof the turbine shaft, the displacement control means including a setscrew threadedly mounted in the housing coaxially with the turbineshaft, a stop pin on the screw, a compression spring around the stop pinand a ball held between the compression spring and the opposite end ofthe turbine shaft, the stop pin and ball being coaxial with the turbineshaft, axial play being permitted between the ball and the oppositeturbine shaft end.
 10. The rotary toothbrush of claim 8, furthercomprising a bushing fixedly mounted in the housing between the shaftmeans section and the turbine wheel, the bushing having an end facedefining a bore through which the turbine shaft extends, the bore havinga diameter greater than the diameter of the turbine shaft, the rotaryshaft means being axially displaceably journaled in the housing, andaxially spaced projections on the shaft means section and the bushingend face for locking engagement upon axial movement of the shaft meansin one direction whereby rotation of the shaft means is prevented anddisengagement upon axial movement of the shaft means in the oppositedirection whereby the shaft means is free to rotate.
 11. The rotarytoothbrush of claim 7, further comprising a floating anti-frictionwasher mounted between the shaft means section and the housing.
 12. Therotary toothbrush of claim 1, further comprising a support for the brushmeans, the shaft means having a conical end and the support having aconforming conical recess to receive the support on the shaft means end,and means for detachably holding the support on the shaft means end. 13.The rotary toothbrush of claim 12, further comprising a protectiveshield for the brush means, the protective shield being detachablymounted on the housing, and a fork-shaped clamping means connecting theshield to the support for free rotation of the shield in respect of, andremoval from, the support.
 14. The rotary toothbrush of claim 1, furthercomprising a water supply and removal tubing attached to the housinginlet and outlet, the tubing including an inner tube connected to theinlet for supplying water under pressure to the housing chamber means,the chamber means including a first chamber adjacent the inlet, a secondchamber wherein the motor means is arranged, a port connecting the firstand second chamBers, and a third chamber wherein the rotary shaft meansis arranged, the second and third chambers being in communication, thechannel means comprising a lateral bore in the rotary shaft means incommunication with the third chamber for receiving rinsing water fromthe third chamber, and the tubing including an outer tube connected tothe outlet for removal of waste water.
 15. the rotary toothbrush ofclaim 14, wherein the means causing the pressure reduction comprises achannel connecting the first chamber to the water outlet.